This invention relates to switch structures, and more specifically relates to a novel manner for fixing a switch terminal board to a thin rigid material switch housing.
Inexpensive, relatively low power switches are well known wherein the stationary switch contacts are fixed to an insulation terminal board. Contact terminals extend through the terminal board to be accessible for connection to appropriate circuits through solder connection or a plug-in type connection. The terminal board is carried adjacent and within the open end of a generally U-shaped thin steel housing. The housing also receives a sliding contact which makes sliding contact with respect to the fixed contacts on the terminal board, and an operating handle which is accessible externally of the housing for moving the sliding contact relative to the fixed contacts. A biasing spring is also provided to ensure good contact between the sliding contact and the fixed contacts fixed to the switch terminal board. The terminal board is commonly attached to the switch housing by small metal tabs which extend from the bottom of switch housing and which are folded around the bottom of the ends of the switch terminal board. These same tabs also hold the entire switch assembly in its assembled condition.
Such switches are frequently mounted on a printed circuit board or other structure in which space is at a premium. Consequently, the switch should be as small as possible, and the thickness of the housing should be as small as possible.
It has been found that the terminal board can be dislodged or loosened relative to the steel housing by moderate forces which tend to pull the terminal board away from the housing. Thus, when the switch is soldered into a printed circuit board, and the handle projects through the housing, an excessive force or impact on the handle will pry open the tabs which fix the switch terminal board to its housing, causing the switch to break apart.
The same problem occurs when the switch is mounted by ears extending from the housing since applying a downward pressure to the handle will press the terminal board away from the housing, and will tend to pry open the mounting tabs.
While thicker steel could be used for the housing to increase the strength of the mounting tabs, space and cost is at a great premium and the thinnest possible steel should be used for the housing.